"This study shows there is great value in seeing patients at routine intervals after surgery in terms of health outcomes," said study co-author Dr. Andrea Schwoerer. She was at the Brody School of Medicine at East Carolina University at the time of the study.

"Unfortunately, many patients, reportedly as many as 50 percent, are lost to follow-up and therefore may not benefit as much as they can from weight-loss surgery, no matter how well it was performed," she added.

In the study, the researchers compared outcomes for more than 51,000 patients. Some had three follow-up visits. These visits occurred at 3, 6 and 12 months after the weight-loss surgery (complete follow-up). Others had only one or two follow-up visits (incomplete follow-up).

After one year, type 2 diabetes remission rates were 62 percent in the complete follow-up group, while the incomplete follow-up group had a remission rate of 57.5 percent. Rates of improvement in type 2 diabetes were 75 percent for the complete group. For the incomplete group, diabetes improvement was 69 percent, the study found.

The complete follow-up group also had greater improvements in high blood pressure and high cholesterol, the researchers said.

The study was to be presented Saturday in New Orleans at ObesityWeek, a meeting hosted by the American Society for Metabolic and Bariatric Surgery (ASMBS) and The Obesity Society.

"We cannot stress enough the importance of follow-up visits and post-operative care," said Dr. Stacy Brethauer, president-elect of ASMBS and a bariatric surgeon at the Cleveland Clinic.

"It could mean the difference between a good and a great result. The most committed patients do best, and we need to find ways to keep all patients engaged for the long-term," she said.

Findings presented at meetings are generally considered preliminary until published in a peer-reviewed journal.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more on weight-loss surgery.